Figure 7: Room temperature spectra and the quantum yield of PL.

(a) Room temperature PL spectra for the 2% P-doped Si NCs with the diameter of 2 nm and 6.6 nm, respectively. (b) Schematic diagram of NIR light emission mechanism in P-doped Si NCs. (c) Quantum yield (QY) of the PL centered at ~890 nm with various P doping concentrations. When the doping concentration is increasing from 0.2% to 4%, the QY is decreasing from 2.30% to 0.14%. (d) QY of ~1300 nm PL with various P doping concentrations. The QY is gradually increased from 0.32% to 0.81% with increasing the P doping concentrations from 0.2% to 3%. With further increasing the P concentration to 4%, the PL QY reduces to 0.23%.